1. Field of the Invention
This invention is directed to an isolating device for a power semiconductor and, more particularly, to such an isolating device that is capable of being triggered upon the occurrence of a predetermined condition.
2. Description of the Related Art
Electrical system installations, such as wind power generators, in which high voltages or currents are switched are equipped nowadays with so-called power modules. A power module contains one or more power semiconductors, e.g. in the form of an IGBT half-bridge. By way of example, a short circuit or ground fault from the power module to the system ground can be effected as a result of the destruction or failure of a single power module. Upon failure of a corresponding power module, it is known to switch off the system installation, remove the destroyed power module and then replace it or repair it. After a fault-free power module has been inserted, the system installation is put into operation again. Such a failure of a power module therefore leads to a sudden or unplanned interruption or disturbance of the operation of the system installation and hence to considerable costs.
Many system installations have a plurality of power modules which are generally operated in parallel to increase the total system power. If a single power module fails in the case of e.g., massive parallelization, the overall system power would actually fall only slightly. Despite possibly intact parallel or redundant power modules, however, operation of the installation cannot be maintained, e.g., in the case of a short circuit in a single defective module. The complete installation must be shut down due to a single defective power module.